The present application relates generally to the field of methods for determining an insulation resistance of an electric DC circuit having at least a first and a second terminal. The application also relates to an insulation resistance measurement circuit for determining an insulation resistance of an electric DC circuit having at least a first and a second terminal.
It may be desirable to determine the insulation resistances between any two terminals in direct current (DC) circuits, such as with two separated DC networks.
It would also be desirable for the ability to make such a determination in the area of electrically-driven vehicles, such as hybrid vehicles or purely electrically-energized vehicles. In such vehicles, a high energy battery is required to provide the required amount of electrical energy necessary for being suitable as a traction battery for a vehicle. Compared with known 12-Volt batteries in vehicles, a traction battery usually requires a considerably higher voltage, in order to keep the required current in an acceptable range. Due to the higher voltage, in order to prevent passengers to get in contact with the high voltage and to avoid an electric shock, it is important to guarantee a sufficient insulation of the battery or, in general, of the electric DC circuit. For safety reasons, it is therefore required to monitor the insulation resistance in a permanent manner.
It would be advantageous to provide an easy to use solution for determination of an insulation resistance of an electric DC circuit which can be implemented with a battery management system in a cost-effective manner. It would be advantageous to provide these or other features as may be apparent from a review of the various exemplary embodiments described herein.